308 research outputs found

    Performance of nano-structured multilayer PVD coating TiAlN/VN in dry high speed milling of aerospace aluminium 7010-T7651

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    A low-friction and wear resistant TiAlN/VN multilayer coating with TiAlN/VN bilayer thickness 3 nm has been grown by using the combined cathodic arc etching and unbalanced magnetron sputtering deposition on high speed steel tools for dry cutting of aluminium alloys. In this paper, in-lab and industrial high speed milling tests have been performed on an aerospace aluminium alloy 7010-T7651. The results show that the TiAlN/VN coated tools achieved lower cutting forces, lower metal surface roughness, and significantly longer tool lifetime by three times over the uncoated tools as a result of the low friction and eliminated tool-metal adhesion. Under the same conditions, a TiAlN based multicomponent coating TiAlCrYN also increased the tool lifetime by up to 100% despite the high cutting forces measured

    Electromagnetic Meson Form Factors in the Salpeter Model

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    We present a covariant scheme to calculate mesonic transitions in the framework of the Salpeter equation for qqˉq\bar{q}-states. The full Bethe Salpeter amplitudes are reconstructed from equal time amplitudes which were obtained in a previous paper\cite{Mue} by solving the Salpeter equation for a confining plus an instanton induced interaction. This method is applied to calculate electromagnetic form factors and decay widths of low lying pseudoscalar and vector mesons including predictions for CEBAF experiments. We also describe the momentum transfer dependence for the processes π0,η,ηγγ\pi^0,\eta,\eta'\rightarrow\gamma\gamma^*.Comment: 22 pages including 10 figure

    Monitoring Antigen Processing for MHC Presentation via Macroautophagy

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    Macroautophagy has recently emerged as an important catabolic process involved not only in innate immunity but also in adaptive immunity. Initially described to deliver intracellular antigens to MHC class II loading compartments, its molecular machinery has now also been described to impact the delivery of extracellular antigens to MHC class II loading compartments through the noncanonical use of the macroautophagy machinery during LC3-associated phagocytosis (LAP). Therefore, in pathological situations (viral or bacterial infections, tumorigenesis) the pathway might be involved in shaping CD4+^{+} T cell responses.In this chapter we describe three basic experiments for the monitoring and manipulation of macroautophagic antigen processing toward MHC class II presentation through the canonical pathway. Firstly, we will discuss how to monitor autophagic flux and autophagosome fusion with MHC class II loading compartments. Secondly, we will show how to target proteins to autophagosomes in order to monitor macroautophagy dependent antigen processing via their enhanced presentation on MHC class II molecules to CD4+^{+} T cells. And finally, we will describe how macroautophagy can be silenced in antigen presenting cells, like human monocyte-derived dendritic cells (DCs)

    Noventa y un años de registros pluviométricos en Montecarlo

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    El presente estudio tuvo como objetivo evaluar la variabilidad de las precipitaciones anuales y determinar la existencia de tendencias en el periodo de tiempo analizado, se agrega a esto el interés en difundir la existencia de estos registros para estudios de variabilidad climática.EEA MontecarloFil: Silva, Fidelina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Montecarlo; ArgentinaFil: Olinuck, Jose Angel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cerro Azul; ArgentinaFil: Münz, R. Actividad Privada; ArgentinaFil: Müller, H. Actividad Privada; Argentin

    CD27 is required for protective lytic EBV antigen-specific CD8+ T-cell expansion

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    Primary immunodeficiencies in the costimulatory molecule CD27 and its ligand, CD70, predispose for pathologies of uncontrolled Epstein-Barr virus (EBV) infection in nearly all affected patients. We demonstrate that both depletion of CD27+ cells and antibody blocking of CD27 interaction with CD70 cause uncontrolled EBV infection in mice with reconstituted human immune system components. While overall CD8+ T-cell expansion and composition are unaltered after antibody blocking of CD27, only some EBV-specific CD8+ T-cell responses, exemplified by early lytic EBV antigen BMLF1-specific CD8+ T cells, are inhibited in their proliferation and killing of EBV-transformed B cells. This suggests that CD27 is not required for all CD8+ T-cell expansions and cytotoxicity but is required for a subset of CD8+ T-cell responses that protect us from EBV pathology

    Towards resolution of the scalar meson nonet enigma

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    By the application of a linear mass spectrum to a composite system of both the pseudoscalar and scalar meson nonets, we find three mass relations for the masses of the scalar states which suggest the qqˉq\bar{q} assignment for the scalar meson nonet: a0(1320),a_0(1320), K0(1430),K_0^\ast (1430), f0(1500),f_0(1500), f0(980).f_0'(980).Comment: 16 pages, LaTe

    Baryon spectra with instanton induced forces

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    Except the vibrational excitations of KK and KK^* mesons, the main features of spectra of mesons composed of quarks uu, dd, and ss can be quite well described by a semirelativistic potential model including instanton induced forces. The spectra of baryons composed of the same quarks is studied using the same model. The results and the limitations of this approach are described. Some possible improvements are suggested.Comment: 5 figure

    Interplay between IL-10, IFN-γ, IL-17A and PD-1 Expressing EBNA1-Specific CD4+ and CD8+ T Cell Responses in the Etiologic Pathway to Endemic Burkitt Lymphoma

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    Children diagnosed with endemic Burkitt lymphoma (eBL) are deficient in interferon-γ (IFN-γ) responses to Epstein–Barr Nuclear Antigen1 (EBNA1), the viral protein that defines the latency I pattern in this B cell tumor. However, the contributions of immune-regulatory cytokines and phenotypes of the EBNA1-specific T cells have not been characterized for eBL. Using a bespoke flow cytometry assay we measured intracellular IFN-γ, IL-10, IL-17A expression and phenotyped CD4+ and CD8+ T cell effector memory subsets specific to EBNA1 for eBL patients compared to two groups of healthy children with divergent malaria exposures. In response to EBNA1 and a malaria antigen (PfSEA-1A), the three study groups exhibited strikingly different cytokine expression and T cell memory profiles. EBNA1-specific IFN-γ-producing CD4+ T cell response rates were lowest in eBL (40%) compared to children with high malaria (84%) and low malaria (66%) exposures (p < 0.0001 and p = 0.0004, respectively). However, eBL patients did not differ in CD8+ T cell response rates or the magnitude of IFN-γ expression. In contrast, eBL children were more likely to have EBNA1-specific CD4+ T cells expressing IL-10, and less likely to have polyfunctional IFN-γ+IL-10+ CD4+ T cells (p = 0.02). They were also more likely to have IFN-γ+IL-17A+, IFN-γ+ and IL-17A+ CD8+ T cell subsets compared to healthy children. Cytokine-producing T cell subsets were predominantly CD45RA+CCR7+ TNAIVE-LIKE cells, yet PD-1, a marker of persistent activation/exhaustion, was more highly expressed by the central memory (TCM) and effector memory (TEM) T cell subsets. In summary, our study suggests that IL-10 mediated immune regulation and depletion of IFN-γ+ EBNA1-specific CD4+ T cells are complementary mechanisms that contribute to impaired T cell cytotoxicity in eBL pathogenesis

    Mrk 421, Mrk 501, and 1ES 1426+428 at 100 GeV with the CELESTE Cherenkov Telescope

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    We have measured the gamma-ray fluxes of the blazars Mrk 421 and Mrk 501 in the energy range between 50 and 350 GeV (1.2 to 8.3 x 10^25 Hz). The detector, called CELESTE, used first 40, then 53 heliostats of the former solar facility "Themis" in the French Pyrenees to collect Cherenkov light generated in atmospheric particle cascades. The signal from Mrk 421 is often strong. We compare its flux with previously published multi-wavelength studies and infer that we are straddling the high energy peak of the spectral energy distribution. The signal from Mrk 501 in 2000 was weak (3.4 sigma). We obtain an upper limit on the flux from 1ES 1426+428 of less than half that of the Crab flux near 100 GeV. The data analysis and understanding of systematic biases have improved compared to previous work, increasing the detector's sensitivity.Comment: 15 pages, 14 figures, accepted to A&A (July 2006) August 19 -- corrected error in author lis

    Quark--antiquark states and their radiative transitions in terms of the spectral integral equation. {\Huge II.} Charmonia

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    In the precedent paper of the authors (hep-ph/0510410), the bbˉb\bar b states were treated in the framework of the spectral integral equation, together with simultaneous calculations of radiative decays of the considered bottomonia. In the present paper, such a study is carried out for the charmonium (ccˉ)(c\bar c) states. We reconstruct the interaction in the ccˉc\bar c-sector on the basis of data for the charmonium levels with JPC=0+J^{PC}=0^{-+}, 11^{--}, 0++0^{++}, 1++1^{++}, 2++2^{++}, 1+1^{+-} and radiative transitions ψ(2S)γχc0(1P)\psi(2S)\to\gamma\chi_{c0}(1P), γχc1(1P)\gamma\chi_{c1}(1P), γχc2(1P)\gamma\chi_{c2}(1P), γηc(1S)\gamma\eta_{c}(1S) and χc0(1P)\chi_{c0}(1P), χc1(1P)\chi_{c1}(1P), χc2(1P)γJ/ψ\chi_{c2}(1P)\to\gamma J/\psi. The ccˉc\bar c levels and their wave functions are calculated for the radial excitations with n6n\le 6. Also, we determine the ccˉc\bar c component of the photon wave function using the e+ee^+e^- annihilation data: e+eJ/ψ(3097)e^+e^- \to J/\psi(3097), ψ(3686)\psi(3686), ψ(3770)\psi(3770), ψ(4040)\psi(4040), ψ(4160) \psi(4160), ψ(4415)\psi(4415) and perform the calculations of the partial widths of the two-photon decays for the n=1n=1 states: ηc0(1S)\eta_{c0}(1S), χc0(1P)\chi_{c0}(1P), χc2(1P)γγ\chi_{c2}(1P)\to\gamma\gamma, and n=2n=2 states: ηc0(2S)γγ\eta_{c0}(2S)\to\gamma\gamma, χc0(2P)\chi_{c0}(2P), χc2(2P)γγ\chi_{c2}(2P)\to \gamma\gamma. We discuss the status of the recently observed ccˉc\bar c states X(3872) and Y(3941): according to our results, the X(3872) can be either χc1(2P)\chi_{c1}(2P) or ηc2(1D)\eta_{c2}(1D), while Y(3941) is χc2(2P)\chi_{c2}(2P).Comment: 24 pages, 9 figure
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